import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class C1_12_2 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n = Integer.parseInt(br.readLine());
        double sum = 0;
        for(int i = 0;i<n;i++){
            int tmp = Integer.parseInt(br.readLine());
            if(tmp%70 == 0){
                sum += 0.1*(tmp/70);
            }else{
                sum += 0.1*(tmp/70+1);
            }
        }
        System.out.printf("%.1f",sum);
    }
}
